Pro Carbon Pumpkin

[Nikko85]

Having come off the back of a very long weekend of work I treated myself to the UK Monsters Carbon Fiber kit for the Lunchbox. Although stated as designed for the lunchbox I was keen to see if I could use it for the Pumpkin instead, as I've got one already with the upgraded arms. I do love they way the Pumpkin looks, but I've not been very inspired to drive it, so will a shiny new chassis make a difference?

The chassis cost £125. You get quite a lot for your money and the build quality was excellent. If it represents value is down to you really!

https://www.ukmonsters.co.uk/lunchbox/index.html 

As @toyolien has done such an amazing build thread on this I decided there wasn't much point doing a full thread, but I'll post my findings as I build, answer any questions and most importantly, see if a Pumpkin can work well!

Making it is pretty easy, everything is in bags with big numbers on them....

and the manual is pretty good.

It's not Tamiya quality, and a few pictures needed a little thinking about and looking forward in the manual to make sure you got it right, but then it's not aimed at a beginner like many Tamiya are.

The chassis is made of two side plates and three pain central plates, which servo as the servo holder and upper and lower decks

The CF is lovely and the tolerances are amazing.

A big plus is that servo can be centrally mounted.

This means that you can have equal length steering rods, which is a nice bonus. The 3mm steering rods are included. These are 50mm. Perhaps it would have been nice if the manual suggest a distance between ball connectors for zero toe, as you have to somewhat guess. These are not turnbuckles and taking off the stock Pumpkin 5mm ball adjusters is a real pain. For reference mine are 41 mm apart, but I guess it depends if you are using the stock steering, which does work with this kit, or the UK monsters upgraded arms, which perhaps is why they don't give a length as there are too many variables...

There are also three main bulkheads, a front, middle and rear. These are CNC aluminium and are really really nice.

The axle is attached with D7 and D8 parts. In this build you will need a full gearbox, D7, D8 and D4 parts, as well as a bumper and axles and wheels. If you want to go all in it might be cheaper to buy those parts and add everything else, but the Pumpkin body is really expensive when bought as separates so probably not.

For my axle I also added a beefed up wheelie bar. This uses two GF01 wheels and a threaded rod to add bracing.

I attached them all, but when putting on the shocks I come to my first issue.

The chassis states that you can use the upgraded rear suspension brace, but actually I think you almost need it, or another mod. I believe the UK monsters  rear suspension braces pushes out the attachment points for the rear suspension a little.  The problem is that with this kit the mounting points for the shocks on the chassis sit further out then they do at the stock axle.

I was able to use some long ball connectors to allow the shocks to be vertical, but it's a little odd. The stock axle shock mounts are already a weak point, so adding longer ball connectors will only make that worse! Looks like this was perhaps designed with the upgrade in mind. It was lucky I had those connectors otherwise I am not sure I could have continued!

[Nikko85]

The rest come together really easily, but on finishing I found my second issue. I should have read or checked, but the site says it can take a LiPO of battery tray can fit a hard case 2s lipo up to a maximum of:

47mm Wide
25mm High
136mm Long (can be extended)

For some reason I just assumed most NiMH batteries would also fit. It's not a stupid assumption, it's a vintage chassis, and many Lunchbox users might still be on NiMH, but none of my 7.2 stick packs fit.

Had it been a few mm wider it would have been ok. I certainly should have asked/checked, but it seems something of  oversight to me, either a few mm wider to allow a stick pack, or perhaps state that NiMH won't work.

I don't use LiPOs, but I do use Li-Ions, so I will use a 21700 pack which will fit nicely, but just something to be aware of. Maybe my NiMH are bigger than some, but I tried three different brands with the same effect.

Edit

My 4500 NiMH do seem to fit, it was just the larger ones. These do fit in all my other Tamiya, so it's worth checking.

[toyolien]

They are such a nicely made chassis, aren't they? Mine is hopefully getting it's fun run this weekend (weather permitting).

Looking forward to see how you mount the Pumpkin body. 

[Grumpy pants]

Another great thread @Nikko85 👏

[Nikko85]

On 6/9/2025 at 9:40 PM, toyolien said:

They are such a nicely made chassis, aren't they? Mine is hopefully getting it's fun run this weekend (weather permitting)

Oh it's incredibly made. 

If you want a performance upgrade the V2 arms and the axle brace will be best, but there was something about this that called out at me!

My fully loaded CW01 was 2224g before, with the upgrade it was 2300g so slightly heavier, but more weight is down low in the form of the bulkhead.

Next up will be installing a smaller battery and fitting the Pumpkin body.

 

 

[Nikko85]

20 hours ago, Grumpy pants said:

Another great thread @Nikko85 👏

Many thanks!

 

[Nikko85]

 So close, but just not going to fit.

Just a very slight widening at the middle points of the sides would allow an NiMH.

No problem, I like Li-ion batteries. To me they are like a milder LiPO.

To make the battery snug I added some sticky foam pads to top of the botton plate. This will hold the battery nice and still.

Now I've got power lets add a motor. A torque tuned should do.

For shocks I am going for classic CVAs in yellow. 

On 6/9/2025 at 9:40 PM, toyolien said:

Looking forward to see how you mount the Pumpkin body. 

I thought this was going to be a really tricky part of the build.

You stated the Pumpkin body would fit but would need a 3D printed solution which gave me the confidence to buy.

I was resigned to a print and actually happy to do some head scratching, but just on the off chance I looked at my spares.

I had some C1 parts from an old MF01X build which looked promising.

For the rear mounts I used some old off-cuts of body posts I had already. I drilled two of the clip holes to 3mm and then put a bolt through these and then into the holes for the body posts.

It couldn't be this easy could it?

It could.

It works perfectly! 

Total coincidence these are wide enough at both points.

Lines up perfectly. If you want this you would need Tamiya 51391 (M05 C parts) you could use a part of the second post for the rear mount.

So they can certainly sell this as perfect for a Pumkin with a small addition!

[MadAtComputer]

Cool build! those yellow CVAs really set it off. What are the plans for paint?

[toyolien]

@Nikko85 Genius way to mount the body. They not only look great, they should have a nice amount of flex compared to the rigid kit Pumpkin body mounts. Nice job.

[Grumpy pants]

9 hours ago, MadAtComputer said:

Cool build! those yellow CVAs really set it off. What are the plans for paint?

Agreed, the yellow CVA’s tie in nicely with the wheels 🎉

[Nikko85]

13 hours ago, MadAtComputer said:

Cool build! those yellow CVAs really set it off. What are the plans for paint?

At the moment it is unpainted. This shell came from a time when I didn't realise black paint would make a black shell look better.

I am going to paint in satin black. I will also swap all the screws for black ones.

I will then add some livery, I might go for full Pumpkin decals, or make and add my own. I will stick with the yellow wheels and CVAs so that will guide me.

[Nikko85]

I spray painted satin and added a few decals.

For now I am going without the Pumpkin decals. I may change my mind but for now I am pretty happy. I've  kept it quite light on decals for for now. I know monster trucks don't usually have numbers, but it seems to tie it together. A large "pumpkin" decal could also work here.

I need to add a driver and test.

But I am pretty happy to say that the chassis works nicely on the Pumpkin.

Edit, driver added: Now it can go as part of the collection

From L-R there's the QD, Carbon Fibre and CR12.

 

[JimBear]

@Nikko85 I really like the satin black - the bare black plastic is okay, but painted looks even better ... I'll make a note of it for the future (still need to get my own QD copy Pumpkin body setup somewhere).